Medical catheters having a balloon mounted thereon are useful in a variety of medical procedures. Balloon catheters may be used to widen a vessel into which the catheter is inserted by dilating the blocked vessel, such as in an angioplasty procedure. Balloon catheters may also be used to expand and/or seat a medical device such as a stent or graft at a desired position within a body lumen. In all of these applications, fluid under pressure may be supplied to the balloon through an inflation lumen in the catheter, thereby expanding the balloon.
It is essential in the manufacture of balloon catheters to properly seal the balloon to the catheter, e.g. by welding. The seal must be able to withstand the high pressures to which it is subjected on inflation of the balloon. A poor seal may result in leakage of inflation fluid and inability to achieve the desired pressure or even rapid loss of pressure and deflation of the balloon. In addition, it is desirable to shape the outside surface of the weld region to provide a smooth transition from the outer shaft to the balloon.
FIG. 1 is an end view of a PRIOR ART balloon catheter 22. Known balloon catheters 22, such as the example shown in FIG. 1, have a preformed balloon 10 which has a center region 26, proximal and distal cones 4, and proximal and distal waists. The waists of the balloon are welded 20 onto the shafts of the catheter 22. The cone 4 of the balloon 10 has a smooth surface and a large outer diameter at one end and a smaller outer diameter at the other end with increasing thickness as the outer diameter of the cone 4 is reduced. As shown in FIG. 1, the center region of the balloon 10 is folded to a small outer diameter but the proximal and distal cones 4 are not folded. This is due to the fact that the balloon 10 is folded after it has been welded onto the shafts 18 of the balloon catheter 22. Thus, there is a relatively bulky transition region between the center region 26 of the balloon 10 and the cone 4 that has an increased outer diameter. This relatively bulky transition region is caused by several factors which include bunching due to the fact that the folding does not end sharply and the increased thickness as the outer diameter of the cone 4 is reduced, as shown in FIG. 1.
The art referred to and/or described above is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. §1 56(a) exists.
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.